diff --git a/.github/workflows/nix-action-8.15.yml b/.github/workflows/nix-action-8.15.yml
index 379319f42..14a5f06fb 100644
--- a/.github/workflows/nix-action-8.15.yml
+++ b/.github/workflows/nix-action-8.15.yml
@@ -190,8 +190,10 @@ name: Nix CI for bundle 8.15
 'on':
   pull_request:
     paths:
-    - .github/workflows/**
+    - .github/workflows/nix-action-8.15.yml
   pull_request_target:
+    paths-ignore:
+    - .github/workflows/nix-action-8.15.yml
     types:
     - opened
     - synchronize
diff --git a/.github/workflows/nix-action-8.16.yml b/.github/workflows/nix-action-8.16.yml
index e69b81cec..21a404361 100644
--- a/.github/workflows/nix-action-8.16.yml
+++ b/.github/workflows/nix-action-8.16.yml
@@ -190,8 +190,10 @@ name: Nix CI for bundle 8.16
 'on':
   pull_request:
     paths:
-    - .github/workflows/**
+    - .github/workflows/nix-action-8.16.yml
   pull_request_target:
+    paths-ignore:
+    - .github/workflows/nix-action-8.16.yml
     types:
     - opened
     - synchronize
diff --git a/.github/workflows/nix-action-8.17.yml b/.github/workflows/nix-action-8.17.yml
index cb4bc3772..8bc32c55d 100644
--- a/.github/workflows/nix-action-8.17.yml
+++ b/.github/workflows/nix-action-8.17.yml
@@ -190,8 +190,10 @@ name: Nix CI for bundle 8.17
 'on':
   pull_request:
     paths:
-    - .github/workflows/**
+    - .github/workflows/nix-action-8.17.yml
   pull_request_target:
+    paths-ignore:
+    - .github/workflows/nix-action-8.17.yml
     types:
     - opened
     - synchronize
diff --git a/.github/workflows/nix-action-8.18.yml b/.github/workflows/nix-action-8.18.yml
index 392a05d22..93401dd06 100644
--- a/.github/workflows/nix-action-8.18.yml
+++ b/.github/workflows/nix-action-8.18.yml
@@ -190,8 +190,10 @@ name: Nix CI for bundle 8.18
 'on':
   pull_request:
     paths:
-    - .github/workflows/**
+    - .github/workflows/nix-action-8.18.yml
   pull_request_target:
+    paths-ignore:
+    - .github/workflows/nix-action-8.18.yml
     types:
     - opened
     - synchronize
diff --git a/.github/workflows/nix-action-master.yml b/.github/workflows/nix-action-master.yml
index 77a773a36..cd21cfa2c 100644
--- a/.github/workflows/nix-action-master.yml
+++ b/.github/workflows/nix-action-master.yml
@@ -158,6 +158,7 @@ jobs:
   mathcomp:
     needs:
     - coq
+    - hierarchy-builder
     runs-on: ubuntu-latest
     steps:
     - name: Determine which commit to initially checkout
@@ -227,6 +228,10 @@ jobs:
       name: 'Building/fetching previous CI target: mathcomp-character'
       run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "master"
         --argstr job "mathcomp-character"
+    - if: steps.stepCheck.outputs.status == 'built'
+      name: 'Building/fetching previous CI target: hierarchy-builder'
+      run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "master"
+        --argstr job "hierarchy-builder"
     - if: steps.stepCheck.outputs.status == 'built'
       name: Building/fetching current CI target
       run: NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle "master"
@@ -492,8 +497,10 @@ name: Nix CI for bundle master
 'on':
   pull_request:
     paths:
-    - .github/workflows/**
+    - .github/workflows/nix-action-master.yml
   pull_request_target:
+    paths-ignore:
+    - .github/workflows/nix-action-master.yml
     types:
     - opened
     - synchronize
diff --git a/.nix/coq-nix-toolbox.nix b/.nix/coq-nix-toolbox.nix
index 8fb619add..b0c3834f0 100644
--- a/.nix/coq-nix-toolbox.nix
+++ b/.nix/coq-nix-toolbox.nix
@@ -1 +1 @@
-"cef6668e637efb2941cbda0ac0f0a435730fa3c1"
+"7e631f043d424ce82f3308824bf64fbfdee04c80"